A stream in name only, the Riddy has not flowed into the river Ivel for well over a year. At its mouth, where people used to throw across makeshift pontoons to cross, there is only cracked earth. Rank grasses from the meadows on either side of the channel have begun to steal into the damp ditch to claim it as their own. They have not yet taken hold in the deeper part of the stream. Under the footbridge, there is still a pool, thinly covered with the duckweed that is typical of droughty late summers here, when the waters are still. Mallards have been here to swim and sup, leaving mazy partings in the floating weed.

In the middle of the pool is an unfamiliar shape that, at first glance, looks like a thin tree stump. My eyes focus on it and perhaps its eyes focus on me. It is a water vole, squatting on its ample haunches on an islet of sedge. It can eat everything within reach, bending down to nip off a long sedge leaf at the base, then holding it in its little forepaws as if it were playing a green clarinet. It begins feeding the leaf into its mouth and I am reminded of a log going into a chipper. The vole's fat cheeks are working constantly, rippling and bulging. If those beady black eyes are watching me, then they are not troubled by what they see, because after a while the animal swings round laboriously, like a fat man rolling off a bar stool, and turns its back on me.

There is a curious paradox about the water vole. Its scientific name Arvicola terrestris means vole of the land and in Europe it is a meadow dweller. Here in Britain, it is exclusively an inhabitant of rivers, streams and water-filled ditches. Unless drizzle turns to downpour, this hunched, furry creature, crouched in its shrinking world, will have to learn continental habits very soon.